


Deception

by thewinchesterlifestyle



Category: Supernatural
Genre: Alpha Castiel, Alpha Lucifer, Alpha/Beta/Omega Dynamics, Alternate Universe - Canon Divergence, Angelic Grace, Angelic Possession, Barebacking, Bottom Dean, Breeding, Butt Plugs, Come Inflation, Dean Doesn't Know, Dildos, Established Castiel/Dean Winchester, Fingering, Grace Sharing, Lucifer Possessing Castiel (Supernatural), M/M, Manipulative Lucifer (Supernatural), Mating Cycles/In Heat, Mildly Dubious Consent, Mistaken Identity, Mpreg, Multiple Orgasms, Nephilim, Non-Consensual Body Modification, Omega Dean, Pregnant Dean, Rough Sex, Season Eleven AU, Size Kink, Top Lucifer, Unplanned Pregnancy, Wicked Grace
Language: English
Status: Completed
Published: 2017-06-08
Updated: 2017-06-08
Packaged: 2018-11-10 22:42:20
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,792
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11136138
Author URL: https://archiveofourown.org/users/thewinchesterlifestyle/pseuds/thewinchesterlifestyle
Summary: There was somethingoffabout Dean Winchester’s voice and Lucifer found himself unexpectedly intrigued. “What’s wrong?” because Castiel would notice the unusual tone and he would be concerned.“My Heat came early, Cas. I need you here…”





	Deception

**Author's Note:**

> I was watching some Casifer videos on YT...I blame those for what you're about to read.
> 
> Ooops?
> 
> \--------------
> 
> I tagged this Castiel/Dean as well because they are mates, it is referenced and them being together is mentioned multiple times throughout the fic. Though the only smut is between Lucifer (who is possessing Castiel) and Dean.

Lucifer leaned back listening to the demon in front of him babbling on about souls and crossroad’s deals. He wanted to wipe every last one of them out and start over but that would come _after_ Amara was dealt with. The Winchesters were bound to come up with something, he’d remove her from the playing field and then he could start cleaning house.

The sound of Castiel’s phone ringing caught his attention.

In front of him the demons had gone silent, staring at him. That was far better than listening to their insipid voices as they tried to suck up to him in the hope to avoid death.

He looked at the caller ID and pressing _answer_ slipped right into Castiel’s voice with a well-practiced ease. “Hello, Dean.”

“ _Hey Cas…I know you’re busy and we should be focusing on Amara but…”_

There was something _off_ about Dean Winchester’s voice and Lucifer found himself unexpectedly intrigued. “What’s wrong?” because Castiel would notice the unusual tone and he would be concerned.

Lucifer was getting pretty good at impersonating Dean Winchester’s angel. Neither Winchester had figured it out though he was primarily interacting with Dean. He wondered if he could trick Sam into giving him his true Vessel before he realized that it was Lucifer and not Castiel wearing Jimmy Novak’s old body.

“ _My Heat came early, Cas. I need you here…”_

 **Oh**.

That was interesting. He hadn’t realized that Castiel had claimed his favorite human. An Alpha angel claiming an Omega human instead of another angel. They must be outraged about that upstairs. And _Dean_ was calling _Castiel_ to come help him through his _Heat_.

Dean Winchester calling his angel mate to knot him and ease the suffering he was no doubt experiencing without an Alpha to take care of him properly.

“ _Cas?_ ” Dean’s voice was rough and Lucifer realized that was because the human had probably tried to put off calling. This was probably one of the last, truly lucid moments Dean would experience between he slipped deeper into his Heat. This was clearly desperation that had him calling Castiel in the middle of everything going on. “ _Can you…I really need you, Cas._ ”

“I was already on my way to the bunker, Dean. I’ll be there soon.”

“ _Oh thank God._ ” Dean’s voice sounded _wrecked_ and anticipation swelled inside of Lucifer. That was Michael’s Vessel, the Righteous Man, and a human who _hated_ Lucifer with every fiber of his being. “ _I’m going out of my mind. Toys aren’t working._ ” It was impossible to miss the way Dean’s voice was breaking and Lucifer could hear the catch in Dean’s voice as well as a low buzzing in the background.

When Lucifer hung up he turned to the demons, snapping out orders and disappeared from Hell as he launched himself through the air. He landed outside of the bunker, anticipation thrumming inside of him at the _treat_ he was going to get to enjoy thanks to Castiel’s _generous_ offer to use his vessel.

Maybe he’d drop down to the Cage and let Michael know how good his true Vessel had felt?

He moved forward, opening the door with the key the Winchesters had given Castiel and moved down the steps. Sam was sitting at the large table, books spread out and frustration coming off him in waves. The heady, thick scent of Omega Heat had started to filter into the room.

“Thank God.” Sam breathed in obvious relief the second he laid eyes on Lucifer, “I’m going to go somewhere that is _not_ here while you take care of him. He should have contacted you the second his Heat started hours ago.” Sam pushed back from the table, “What’s the point of having a mate if you don’t bother contacting them when you _know_ your Heat is coming up?”

There was a flush of embarrassment about the whole thing on Sam’s face and Lucifer felt a curl of amusement. No doubt Sam had been able to hear Dean attempting to deal with his Heat and he’d been waiting for _Castiel_ to show up to take care of Dean before abandoning ship.

“I’m sorry, Sam. I came as quickly as I could.”

“That’s ok, Cas.” A hand clapped on his shoulder, gave it a squeeze. “Just _please_ take care of him. He’s terrible at asking for help.”

With a quickly muttered _bye Cas_ Sam went up the stairs and seconds later the heavy door bolted into place leaving Lucifer in the bunker, _alone_ , with a vulnerable and needy Dean Winchester who would only see _Castiel_ when he looked at Lucifer’s current vessel.

He whistled lowly as he walked through the bunker following the increasingly thick and temptingly sweet scent of a _very fertile Omega_ in Heat. Casually he dug into Castiel’s memories, knowing to search for ones related to Dean and _mate_ , to see how the angel typically handled Dean.

Lucifer came to a jarring stop when he saw that Castiel used his grace to prevent himself from creating a Nephilim instead of Dean using birth control. A slow, pleased smile tugged at his borrowed lips.

It hadn’t been something he’d considered before but as Michael’s true Vessel, created to be durable and to contain an archangel without damaging, Dean would be the _perfect_ carrier for a Nephilim. Unlike a normal human who would forfeit their life while giving birth to one Dean’s body would be equipped to survive _and_ to produce even more Nephilim.

His pace picked up and the sound of needy whining caught his attention.

“Thank you, _Cas_ , for such a lovely little gift.” Lucifer murmured to himself as he turned the doorknob to the room he knew was Dean Winchester’s. The heavy scent of a fertile in-Heat Omega slammed into him and Lucifer’s cock instantly hardened to a painful ache.

It had been _so long_ and he’d never been able to breed an Omega. He’d fucked plenty but he’d been banished to the Cage before he’d ever gotten a chance to enjoy a mating season. Thanks to Castiel he would finally get to experience breeding an Omega.

He looked at the bed, where a completely naked and whimpering Dean was fucking himself with a buzzing toy, and Lucifer didn’t hesitate to step into the room. Omega gold eyes flashed over to him, clouded with need and arousal, as Dean’s wrist continued to work and Lucifer could see the mess of slick coating the toy.

He might spare Dean after he’d gotten enough fledglings from him. Michael’s Vessel was a very tempting, sinful sight lost to his Heat and Dean’s scent was mouthwatering. It would be a shame to dispose of an Omega who could provide him with very strong fledglings and Dean would make a fine trophy when he took over.

“ _Alpha_.” Dean’s voice was wrecked and without much thought the clothes that adorned Castiel’s vessel were gone, banished to a nearby chair, as Lucifer stalked forward. “Please, Cas, please I can’t—”

“ _Shhhhh_.” He crooned as he climbed onto the bed, pulling out the toy and discarding it. Dean’s cunt gaped beautifully, leaking slick and rhythmically clenching as it sought a knot.

 _His knot_.

“I’m going to give you exactly what you need.” In front of him Dean eagerly rolled over, assuming the universal position to be mounted with his glorious ass raised and his cheek resting against the sheets. Dean spread his knees far apart and arched his back in offering.

After admiring the sight for a few seconds Lucifer gripped his cock and moved up behind Dean, gazing lustfully at the Omega’s loose cunt, before he started sinking in. His eyes hooded in pleasure, his breathing hitched and his grace thrummed with the knowledge of what was to come.

His first time breeding an Omega, his first-time siring fledglings, and it was going to be with _Michael’s Vessel_. He was going to _ruin_ Dean Winchester. He would pay the human back for helping to shove him back into the Cage and take his compensation from the fledglings he’d fuck into Dean’s womb.

“So good.” he breathed out as he pressed balls deep into the warm, wet and clenching cunt of a very needy Omega. “You’re going to be good for me, aren’t you? A good Omega for _your Alpha_?”

Delight flashed through him, something wicked filling his gaze along with arousal, as Dean whined and pushed back into him. “Yes, Alpha, _yes_. Please please I need—”

“What do you need?”

Dean always begged for _it_ during Heats with Castiel even when neither of them had an intention to follow through but Lucifer had every single intention of using Dean in the exact way he was meant to be used.

For breeding.

“Your knot.” Dean’s voice shook as Lucifer edged back out, “Please Alpha… _breed me please please I need it please Cas please._ ”

Lucifer slammed inside, the bed groaned in protest at the force, while his fingers dug into the flesh of Dean’s hips. He wasted little time in rapidly, _viciously_ , fucking into the warm and pliant Omega underneath him.

Needy whimpers and broken sounding moans escaped Dean’s parted lips as his cunt repeatedly clenched down on Lucifer’s cock. “ _Ohhhh oh Alpha yes yes yes Cas please…harder Alpha harder_!”

Lucifer’s grace flashed in his eyes, wings unseen by the human beneath him arching, as Lucifer let himself go barely mindful of the fact that he was fucking and breeding a human instead of a more durable Omega angel. But he had enough control not to damage the future barrier of his fledglings.

The slap of skin against skin echoed in the room, underneath them the bed creaked repeatedly in protest at the power behind each thrust, and Dean had been reduced to wrecked moans. Lucifer bared his teeth in a low snarl, grace surging, as his knot started to catch on Dean’s cunt.

It popped in and out, pulling low keens from Dean’s lips, before he slammed deep and rutted roughly up against Dean. His growing knot slipped into Dean’s loosened cunt, sunk in and swelled to tie them together.

Lucifer’s orgasm slammed into him, pleasure rushing through his grace and borrowed vessel.

His release spilled into Dean, coating his slick soaked channel and filling Dean up. Lucifer could feel the way Dean clamped down on him as the Omega came with a wail, shuddering and going limp, while his inner muscles greedily started to milk Lucifer’s thick knot.

“Fuck, Cas.” Dean’s voice was rough as he laid there under Lucifer, breathing starting to regulate, as a brief respite from the usual frenzy an Omega experienced filled him. In a few hours even that would be gone and Dean would be completely lost to the Omega instinct to be knotted and bred by an Alpha until he’d been fucked full. The only thing Dean would be able to remember from it would be the need, heat and pleasure from an Alpha knotting him. “Didn’t want to bother you but I’m glad you came…”

“Of course I came.”

How on Earth could he pass up _this_ kind of opportunity?

If Castiel woke up long enough from his willful distancing of Lucifer’s actions he was more than sure the angel would be fighting tooth and nail for control over his vessel to prevent Lucifer from breeding Dean with _his_ fledglings.

“Didn’t think it would be so bad. I only lasted a couple hours before I called…” Dean mumbled, cunt still rhythmically clenching down on Lucifer’s knot and sending delicious bursts of pleasure racing through his very grace. He lazily fucked his knot in Dean’s cunt, relishing each brush against Dean’s prostate causing the Omega to clamp down even tighter. “You remembered to be careful, right? No Nephilim?”

“Of course, Dean.” He draped himself over Dean’s warm body, rocking up against the human and taking every bit of pleasure he could as his hand crept down to rest against Dean’s flat belly.

Lucifer could already imagine it swelling beautifully, large and round, with _his_ fledglings and how the angels would revolt at the very thought of a Nephilim from _him_. Castiel would be crushed, Dean destroyed and he would get to watch the entire show.

He didn’t roll them onto their sides, like Castiel would do, because Lucifer was a fan of the traditional position for angels mating and breeding. The dominant always remained on top, knot firmly caught, while the submissive remained underneath being bred.

Though he might entertain the thought of Dean desperately fucking himself down on his cock trying to get a knot. It would certainly make it more interesting when Dean discovered who had spent his Heat with him.

Idly he tested the strength of Dean’s body, he could _feel_ the difference in the durability, and felt nothing but pleased at his choice. He might have to bring Dean down to the Cage and show off his future fledglings to Michael.

Eventually his knot slipped free, his come and Dean’s slick lazily spilling out of Dean’s gaping cunt, causing a low whine to escape Dean.

Dean collapsed onto the sheets on his belly, sighing and shoving his face against the pillow. Lucifer watched him, took in Dean’s completely unguarded and vulnerable position, before gazing at the Righteous Man’s soul.

It was bright.

Radiant even.

He could see the effort Castiel had placed in healing the damage Hell had wrought, little bursts of Castiel’s own grace woven into Dean’s unique and rare soul. It was tempting to taint the mark Castiel had left on Dean’s soul, it had been healed from the human’s shoulder but any angel who looked would see it.

It was impossible to miss after all.

The mark on the back of Dean’s neck, the broken bonding gland, was obvious to _all_ who looked. He lightly touched it, imaging breaking the bond and forming his own, before he moved away from it. It would be more enjoyable to bite into that mark, shattering the bond, when Dean was swollen with his fledglings and moaning for his knot.

Lucifer trailed his hands over Dean’s pliant form, examining the human before him, as Dean simply laid there with a sated look on his face allowing Lucifer’s touch.

The touch Dean thought was Castiel’s.

Lazily he moved his fingers down, along the curve of Dean’s back and the swell of his round ass, before pressing inside Dean’s loose cunt. It earned him a low whine and the thickening of Dean’s scent as arousal twisted through the human.

It was fascinating watching Dean pressing into his touch, wordlessly begging for more, as Dean tightened down on his fingers while Lucifer languidly fucked them in and out of Dean. He could smell the way Dean’s Heat was building back up, twisting through the Omega’s warm body, as slowly but surely Dean slipped right back into begging for a knot.

He didn’t haul Dean up and instead straddled his thighs and sunk back in Dean’s cunt with satisfaction. His knees dug into the mattress as he braced himself and started thrusting forward. Dean’s body jerked and moved with each snap of his hips, the Omega fisting the sheets and yanking as a series of moans escaped out into the room.

There was little point in dragging it out. He was fucking to breed and humans typically had Heats that lasted three to five days depending on the Omega and whether they’d been bred early on in their Heat.

Part of Lucifer hoped he would have the full five days of fucking, knotting and breeding Dean as the Omega got increasingly desperate and needy to the point that Lucifer could completely drop the Castiel façade in favor of himself.

It wasn’t like an Omega ever remembered much of anything after the first day. He knew that much from his observation and Castiel’s own memories of past Heats with Dean Winchester.

Lucifer snapped his hips forward, vigorously fucking, while Dean panted and shuddered in pleasure under him. “Alpha Alpha Alpha please ohhh yes there there there please Alpha. Need your knot. So empty. So fucking empty, Alpha.”

 _You won’t be for long._ He thought with smug triumph. Dean wouldn’t be leaving this room until he was successfully bred and carried _Lucifer’s_ fledgling. A Nephilim from an archangel of Lucifer’s caliber and the human meant to house Michael.

There wouldn’t be a stronger fledgling in existence.

His balls slapped against Dean along with his hips as Lucifer drove forward repeatedly, feeling his knot growing and finally rutting up against Dean until it caught inside once more. Lucifer moaned, throwing himself into the pleasure of breeding, while Dean gasped and shuddered through his own orgasm.

“Mmmmm.” Dean’s eyes were hooded, his freckled cheeks flush and his body was completely limp underneath Lucifer. The human didn’t have the faintest idea of the threat knotted in his cunt or the power lurking beneath the body pinning his down.

* * *

Three days into Dean’s Heat and the Omega had been long since lost to the instincts of an Omega needing to be bred. Lucifer didn’t even think Dean knew where he was but it hadn’t taken much to get the needy, desperate-for-a-knot Omega to call him by his actual name.

An Omega desperate for a knot and far gone into their Heat would do _anything_ for a knot without remembering it. And if by some miracle Dean did remember for Lucifer wanted to reveal he’d simply remove the memory.

“You’re not getting my knot unless you say it.” he purred in a delightful taunt, hard Alpha cock nestled in Dean’s soaked cunt and not moving, while Dean practically sobbed with desperation under him.

It was the only redeemable thing he’d found about humans.

This particular one held a hint of beauty when in the throes of his Heat and desperation.

“ _Please, Alpha, please!_ ” Dean’s voice was rough, scratchy and broken, as he tried shoving back into Lucifer but Lucifer kept a firm grip on the back of Dean’s neck keeping the Omega pliant below him.

“Not what I asked for, _Omega_. Beg me. Beg _Lucifer_ to fuck your womb full.”

Another rough sound escaped Dean and he could see the need in every inch of the human caught below him. He wondered if breeding an Omega angel would be this satisfying.

“ _Lucifer please please please. I need a knot. Need it._ ” Dean had taken to babbling, “ _Please breed me. Please Lucifer please._ ”

“Good, Omega. You’re such a good, obedient human when you want a knot, aren’t you?”

“Yes! Be so good. Please I need…I need a knot. Please please please please.”

“Since you asked so nicely.” Lucifer didn’t waste any time and immediately started pounding into Dean once again. The begging turned back into choked gasps, whines and wrecked whimpers that drove him forward.

He’d never imagined enjoying this so much.

“ _Alpha…please please ohhhhh_ … _Lucifer_!” Dean’s instincts were screaming and writhing inside of him, Lucifer could see it in Dean’s body and in his soul, as his mind fed him everything he needed to say to get exactly what he was craving. With enough conditioning, even an Omega so lost to need could learn and adapt to get what their body urgently needed.

This memory would destroy Castiel.

His lips curved in a wicked smirk before he slammed forward, rutting up against Dean and groaning lowly in pleasure as his knot once more slipped into Dean and swelled to lock him in Dean’s cunt.

Lucifer’s grace flared brightly in his eyes, his teeth bared in a low snarl, as thick ropes of come emptied into Dean’s warm cunt. He could feel the way Dean’s inner muscles hungrily milked his knot. Another flare and he noted a sudden warm, bright tiny flare of new grace.

Dean Winchester had caught.

Victory surged through him, the thrill of success and accomplishment a warm and heady rush that had him grinding up against Dean’s ass and relishing the tight clench each time he fucked his knot into Dean.

“Such a good Omega.” He crooned in pleasure, “So good catching for your Alpha on our first attempt.” Lucifer casually let his grace, bright and hot, twine around Dean’s soul as he coaxed it into yielding to him with surprising ease. At this point, lost to need and pleasure, he could probably get this human to say _yes_ to him but Dean wasn’t for that. “At least one of you humans are useful for something.”

Dean didn’t seem to hear him, eyes glazed with arousal and cheeks flushed with heat, while he panted lowly and his heart calmed.

“I’m going to enjoy seeing the realization in your eyes.” Lucifer rocked up against Dean, releasing another load into Dean’s sloppy, thoroughly used and bred cunt. His hand reached undeath to the bulge of Dean’s come swollen belly, still thrusting shortly against Dean, as the knowledge of the growing fledgling inside of Dean kept him in smug satisfaction. “Let’s see if you can’t give me two. I’m feeling greedy.”

When his knot slipped free Lucifer didn’t bother pulling out, his cock already hardening and Dean whining beneath him, as he started fucking into Dean again. He easily wrapped Dean in his grace, reinforcing the human so Dean could withstand more of his strength, and Lucifer let himself go.

He viciously pounded into Dean, slamming up against Dean’s ass. Dean couldn’t hope to meet his pace and the Omega didn’t bother trying. Instead Dean remained pinned below him, whining and moaning, while Lucifer kept fucking harshly into him.

Lucifer knotted Dean ten more times, pumping his come repeatedly into Dean’s cunt, until Dean’s Heat started to fade and a second beautiful flare of new grace appeared in Dean’s womb.

He could already feel the power in both fledglings.

As Lucifer focused on the growing grace Dean curled on his side, cunt plugged and belly round with days of Lucifer fucking him. After days of near nonstop breeding it was more than obvious Dean needed rest without Lucifer’s grace bolstering him. He knew from looking at Castiel’s memories that the angel didn’t typically use his grace to sustain Dean and prevent the need for basic human needs but Lucifer had possessed no interest in being inconvenienced by human necessities.

The two fledglings growing inside of Dean’s womb were a testament to the success in his methods.

He shifted Dean over onto his back, rested a hand right over Dean’s womb and with a brief flare of grace carefully warded Dean against other beings recognizing just what was growing inside the Omega.

It wouldn’t do for anyone to realize that Lucifer had fathered two Nephilim with the Righteous Man. Not until he was ready for them to know.

**Author's Note:**

> This came to me randomly and I don't know if anyone has actually done this. I also know we learned normal humans can't survive birthing a Nephilim BUT I'm going with the theory that a human equipped to handle an archangel like Michael could birth a Nephilim without death. Dean is supposed to be a vessel for angelic grace...it's just going to be a different kind.
> 
> Sooooooooo...how did I do? Did I nail it?


End file.
